Duration of Diabetes is Associated with Stroke Risk

The risk of suffering a stroke increases with the duration of type 2 diabetes, according to a new study by Associate Professor of Epidemiology Mitchell Elkind, MD, and colleagues at Columbia University Medical Center. Stroke risk triples for those who have diabetes for 10 years or more, according to the study, which was published in the American Heart Association Journal Stroke.

“The findings emphasize the chronic nature of diabetes and the fact that it damages the blood vessels over time,” says Dr. Elkind, who is senior author and also a Columbia professor of Neurology.

Researchers followed nearly 3,300 people, average age 69, who had never had a stroke. When the study began, nearly 22% of participants had diabetes, and after an average of 9 years of follow-up, an additional 10% had developed diabetes. The researchers controlled for factors such as age, smoking history, and history of heart disease.

The study looked exclusively at ischemic strokes, which occur when blood to the brain is blocked because of a clot. Diabetics may be at an increased risk for stroke because of thicker plaque in neck arteries, higher prevalence of hypertension, accelerated vascular complications, and clotting abnormalities.

Although stroke rates have been declining in recent years, increased incidence of diabetes at younger ages than before may lead to a higher stroke burden in the future, noted Dr. Elkind. Over half of the nearly 26 million Americans with diabetes are younger than age 65, according to the American Diabetes Association.

Young people should try to delay the onset of diabetes through regular exercise, a healthy diet, regular doctors’ visits, and avoiding smoking, according to Dr. Elkind.

“We used to think of type 2 diabetes as a disease people get when they are older, after a lifetime of poor dietary habits,” said Dr. Elkind. “But the age at diagnosis is getting younger and younger because of the obesity problem among young people.”

The results are part of a long-term Northern Manhattan Study (NOMAS), based at Columbia, which examines stroke and stroke risk factors in a population in Washington Heights.